IMPORTANT:AttackDefense Labs is included with a Pentester Academy subscription! Upgrade Now to access over 1800+ Labs.

Already a Pentester Academy student? Your access will continue uninterrupted. Please use the same Google account to login here.

Not a Pentester Academy student? Try our Free Communitiy Labs

PwnKit (CVE-2021-4034)

cve-2021 | Level: Easy  | Total Lab Runs: 0 | Premium Lab

Lab Scoreboard

Qualys team discovered a Local Privilege Escalation (from any user to root) in Polkit's pkexec, a SUID-root program that is installed by default on every major Linux distribution.


It is a memory corruption vulnerability discovered in the pkexec command (installed on all major Linux distributions), dubbed PwnKit, and assigned CVE-2021-4034. It was announced on January 25, 2022. The vulnerability dates back to the original distribution from 2009. The vulnerability received a CVSS score of 7.8 ("High severity"), reflecting serious factors involved in a possible exploit: unprivileged users can gain full root privileges, regardless of the underlying machine architecture or whether the polkit daemon is running or not.


In this lab, we will learn how to exploit the local privilege escalation vulnerability in the pkexec utility in a realistic environment to gain root access on the machine.

In this lab environment, the user will get access to an Ubuntu CLI instance. The provided Ubuntu instance has a vulnerable version of the Polkit's pkexec utility.

Objective: Exploit the local privilege escalation vulnerability in the Polkit's pkexec utility to gain root access and retrieve the flag!

The following activities are strictly prohibited on this website unless otherwise explicitly stated as allowed in the mission statement:

  • Using automated scanners
  • Using brute force attacks
  • Denial of Service attacks
  • Attacking other student machines in challenges where you might achieve a shell on the vulnerable system
  • Attacking the lab infrastructure

Users violating the above will be either temporarily or permanently banned from the website. 

If you are unsure about an activity, then please contact support to confirm that it is allowed on our website.

Technical Support for this Lab:

There is a reason we provide unlimited lab time: you can take as much time as you need to solve a lab. However, we realize that sometimes hints might be necessary to keep you motivated!

We currently provide technical support limited to:

  • Giving hints for a lab exercise
  • In rare circumstances, if you have totally given up (NO!!!) then tell you how to solve it. This will be limited to sharing the solution video or lab report
  • A lab exercise fails to load or has errors in it

If you need technical support, please email  clearly mention the name and link of the lab exercise and other essential details. The more descriptive you are, the faster we can help you. We will get back to you within 24 hours or less. 

For adminitrative queries, billing, enterprise accounts etc. please email